A conventional image reading apparatus reads an image on a sheet by acquiring reflected light when light of each color including red, green and blue is irradiated by a light source onto a read target, such as a sheet. In this case, the light source moves in a sub-scanning direction and sequentially switches among red, green and blue light to emit the light of different color to the sheet at different times. Since the light source moves in the sub-scanning direction during the switching, light of different color is irradiated onto different positions of the sheet. For this reason, instead of reading an image with the red, green and blue light overlapped with each other, the image is read with color shifting. In view of such a problem, there is a method of converting the acquired reflected light to an electric signal indicating a strength of the reflected light, and correcting a phase of the electric signal. By correcting the phase of the electric signal, the color shift is corrected, and an image that is close to the image that is read when the red, green and blue light is emitted to the same position on the sheet, can be acquired. However, in the conventional method, although the image read by the image reading apparatus is an image in which the color shift is corrected, there is a case in which a color of the image is changed. The change of color refers to that a color of the image read by the image reading apparatus is different from the color of the read target.